The invention is directed to a fuel injection valve and a method for adjusting the static fuel quantity, ejected during the steady opening state, of a fuel injection valve.
In the fuel injection valve known for example from German Patent Disclosure Document DE 35 33 521 A1, the stroke of the valve closing body and thus the static flow quantity of a fluid output ejected during the steady opening state of the fuel injection valve, is adjusted in that the end face of the nozzle body on which the stop plate that defines the remanent air gap of the armature with respect to the core is ground down. However, this valve and the adjusting method employed has the disadvantage that the end face of the nozzle body can be ground down only after the valve has been partly dismantled, making it very difficult and complicated to adjust the valve needle stroke exactly.
A fuel injection valve having a valve seat body that has at least one injection port is described in German Patent Disclosure Document DE 38 31 196 A1. The valve seat body is pressed into the longitudinal opening of the nozzle holder, and the depth to which it is pressed defines the valve needle stroke. Although the valve needle stroke can be adjusted in the completely installed injection valve, nevertheless the danger of chip formation at the valve seat body and/or the seat holder when the valve seat body is pressed into the nozzle holder still exists.
In the perforated plate-type fuel injection valve, known for instance from German Patent Disclosure Document DE 36 40 830 A1, the injection ports of the perforated plate have predetermined opening cross sections that vary the static fuel quantity. To adjust the static fuel quantity, the exact flow quantity through individual perforated plates is measured in order to combine a perforated plate with a particular valve group that has a known valve stroke. Then the fuel injection valve is installed and provided with a fuel filter, but the danger exists that the static fuel quantity of the valve will be undesirably changed in the process.
An electromagnetically actuatable fuel injection valve has also been proposed, the tubular inner pole of which has a throughbore extending concentrically with a longitudinal valve axis. An adjusting bush that serves to adjust the restoring spring is pressed into this throughbore, and a fixed, nonadjustable throttle body is disposed in the longitudinal opening of this adjusting bush.